mysql查询七十多万条数据内存溢出，求助。。。

[weixin_38063296]

日志如下：
System.OutOfMemoryException: 引发类型为“System.OutOfMemoryException”的异常。
   在 MySql.Data.Types.MySqlString.MySql.Data.Types.IMySqlValue.ReadValue(MySqlPacket packet, Int64 length, Boolean nullVal)
   在 MySql.Data.MySqlClient.NativeDriver.ReadColumnValue(Int32 index, MySqlField field, IMySqlValue valObject)
   在 MySql.Data.MySqlClient.Driver.ReadColumnValue(Int32 index, MySqlField field, IMySqlValue value)
   在 MySql.Data.MySqlClient.ResultSet.get_Item(Int32 index)
   在 MySql.Data.MySqlClient.MySqlDataReader.GetFieldValue(Int32 index, Boolean checkNull)
   在 MySql.Data.MySqlClient.MySqlDataReader.GetValue(Int32 i)
   在 MySql.Data.MySqlClient.MySqlDataReader.GetValues(Object[] values)
   在 System.Data.ProviderBase.DataReaderContainer.CommonLanguageSubsetDataReader.GetValues(Object[] values)
   在 System.Data.ProviderBase.SchemaMapping.LoadDataRow()
   在 System.Data.Common.DataAdapter.FillLoadDataRow(SchemaMapping mapping)
   在 System.Data.Common.DataAdapter.FillFromReader(DataSet dataset, DataTable datatable, String srcTable, DataReaderContainer dataReader, Int32 startRecord, Int32 maxRecords, DataColumn parentChapterColumn, Object parentChapterValue)
   在 System.Data.Common.DataAdapter.Fill(DataSet dataSet, String srcTable, IDataReader dataReader, Int32 startRecord, Int32 maxRecords)
   在 System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
   在 System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
   在 System.Data.Common.DbDataAdapter.Fill(DataSet dataSet)